Technical Field
The present disclosure relates to a field of signal processing methods. More particularly, the present disclosure relates to methods and systems for processing a pressure sensing signal.
Description of Related Art
In recent years, with the increasing advance of touching sensing technology, a touch panel has become a necessary module in display devices. The touch panel which provides a pressure sensitive function has drawn more and more attention. In general, a resistance-type pressure sensitive module may include touch electrodes which are made from piezoresistive materials. By detecting a magnitude of electrical resistance variations of the touch electrodes after being pressed, the resistance-type pressure sensitive module may determine the magnitude of the pressing force based on resistance variations corresponding to the magnitude of the pressing force. However, an existing pressure sensitive module may generate signal noise affected by the environment. For example, under the influence of temperature variation, structural variation or environmental variation, the resistance of the pressure sensitive module may vary, so as to increase or reduce a magnitude of the signal, and such signal noise caused by ambient factors may result in pressure sensing distortions.
For example, the commonly-used piezoresistive material, indium tin oxide (ITO), may generate resistance variation caused by the temperature and another variations. Compared to the resistance variation of a deformation caused by the pressing force, the resistance variations due to environmental variation may not be ignored. The pressure sensitive module formed by indium tin oxide may detect a resistance variation ΔR after being pressed, but the resistance variation ΔR is a result of an interaction of the temperature and the deformation. The deformation is positively correlated to the pressing force, however, since the pressure sensitive module may not detect the temperature variation after being pressed, and the pressure sensitive module may not acquire the resistance variation caused by the temperature certainly, the pressure sensitive unit cannot eliminate the above ambient factors of the environmental variations to determine the magnitude of the pressing force based on the resistance variation alone.
In order to solve the above problems, a pressure sensitive module having a plurality of touch electrode layers may be utilized to determine the magnitude of the pressing force by processing a temperature compensation interaction between the touch electrode layers and calculating the resistance variation of the touch electrode layers. However, such a configuration requires an increase in the amount of piezoresistive materials and number of manufacturing processes, and may waste material and reduce the yield of products, while also increasing thickness of the pressure sensitive module, which may not conform to a trend toward thinner touch panels.